Abstract : How do active matters at different length scales, respond to various mechanical stimuli like rigidity, geometry and topography? This question has generated significant research interest in recent times. In this talk we will discuss “Mechanosensing”, the process by which cells sense and respond to such mechanical cues, at various length scales. First part of the talk will focus on the growth of multicellular spheroids in confined geometry. We developed a microfluidic technique to produce 3D cell-based assays and to interrogate the interplay between tumor growth and mechanics in-vitro. Our experimental findings suggest that confinement induces a drastic cellular reorganization, including increased motility of peripheral cells. In the second part of the talk, we will discuss the rigidity sensing at cellular scale. Our in-vitro experiments performed using micro-force sensing arrays(μFSA) and theoretical modelling demonstrate that, the actin cytoskeleton shows different rheological behavior depending on the substate stiffness. On softer substrate it behaves like a fluid, whereas on stiffer substrate we see a solid like behaviour. Furthermore, we find the emergence of orientational order with increasing substrate stiffness, where the actin stress fibres show a isotropic to nematic transition. Altogether our research provides new insights to understand the interaction of cells with their microenvironments.